Patent application title: STEERING APPARATUS

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Abstract:

It might happen that an inner column 3 is released from telescopic
clamping and tilt clamping by an outer column 4 in a state before a
vehicle fitting bracket 2 is fitted to a vehicle body. When a male
steering shaft 6 is to escape from a female steering shaft 5, a come-out
preventive member 7 is intruded into an inner peripheral annular groove
52 vicinal to an end portion of a female spline 51 on the front side with
respect to the vehicle body. Then, the come-out preventive member 7 abuts
on a shoulder portion 521 of the end portion, on the front side with
respect to the vehicle body, of the inner peripheral annular groove 52,
thereby surely enabling the male steering shaft 6 from escaping out of
the female steering shaft 5.

Claims:

1. A steering apparatus comprising: an inner column; an outer column
being fitted to the inner column so as to be relatively movable in an
axial direction; a clamp mechanism fixing a relative position of the
outer column to the inner column; a female steering shaft being rotatably
supported on any one of the inner column and the outer column and having
its inner peripheral surface formed with a female spline; and a male
steering shaft being rotatably supported on the other of the inner column
and the outer column, having its outer peripheral surface provided with a
male spline inserted and fitted in the female spline, and being capable
of moving in the axial direction with respect to the female steering
shaft and transferring torque thereto, the steering apparatus being
capable of adjusting a telescopic position of a steering wheel fitted to
the female steering shaft or the male steering shaft, wherein the female
steering shaft and the male steering shaft are provided with a come-out
preventive mechanism for preventing an axial escape of the male steering
shaft from the female steering shaft in a state where a fitting portion
between the female spline and the male spline remains.

2. The steering apparatus according to claim 1, wherein the come-out
preventive mechanism is configured by including: an outer peripheral side
annular groove formed in the male spline in a peripheral direction; a
resiliently deformable ring-shaped member fitted in the outer peripheral
side annular groove; and a diameter enlarged portion provided at one
portion of the female spline in the axial direction or provided
adjacently to an end portion on the side opposite to the male spline
insertion side, the diameter enlarged portion is formed to have a
diameter larger than a tooth tip circle of the female spline and have a
widthwise dimension larger than a widthwise dimension of the ring-shaped
member and is provided in a position where the fitting portion between
the female spline and the male spline remains in such a state that a
relative position of the female steering shaft to the male steering shaft
becomes a position in which the diameter enlarged portion and the outer
peripheral side annular groove are superposed in a radial direction, and
the ring-shaped member gets resiliently deformed upon the male spline
abutting on the female spline when inserted into the female spline,
enables the male spline to move with respect to the female spline in the
axial direction, resiliently returns to enlarge in diameter from a
diameter reduced state when the female steering shaft and the male
steering shaft make the relative movements in such a direction as to
escape as well as in the axial direction in a state after fitting the
female spline and the male spline together but before mounting the
steering apparatus on the vehicle body, and abuts on the female spline,
thereby preventing the axial escape of the male steering shaft from the
female steering shaft.

3. The steering apparatus according to claim 2, wherein an end portion of
the female spline on the male spline insertion side is provided with a
chamfer portion; and a large diameter portion having a diameter larger
than a tooth bottom circle of the female spline is formed at a portion of
the inner peripheral surface of the female steering shaft, i.e., at a
portion on the side opposite to the male spline insertion side, the outer
peripheral side annular groove of the male spline has its bottom surface
formed closer to an inner diametrical side than the tooth bottom circle
of the male spline, the ring-shaped member is provided with a chamfer
portion on an outer diametrical side, has its outer diameter of which a
dimension is formed smaller than a diameter of a tooth tip face of the
male spline but larger than a diameter of the tooth bottom circle of the
male spline and is positioned within a range of a radial thickness of the
chamfer portion provided at the female spline of the female steering
shaft of which the outer peripheral surface is disposed coaxially with
the male steering shaft as viewed from the axial direction of the male
steering shaft, the ring-shaped member, when the male spline is inserted
into the female spline, because of the chamfer portion on the outer
diametrical side sliding on the chamfer portion of the female spline,
gets resiliently deformed to reduce in diameter and gets movable in the
axial direction within the outer peripheral side annular groove, and a
gap exists between the outer peripheral surface of the ring-shaped member
and the inner peripheral surface of the large diameter portion when the
ring-shaped member is positioned at the large diameter portion of the
female steering shaft.

4. The steering apparatus according to claim 2, wherein when the female
steering shaft and the male steering shaft make the relative movements in
the escaping direction as well as in the axial direction, an abutment
portion of the female spline on which the ring-shaped member abuts at the
diameter enlarged portion is formed on the face vertical to the center
axis of the female steering shaft.

5. The steering apparatus according to claim 4, wherein the diameter
enlarged portion is formed in a position deviating on such a side that a
telescopic adjustment position gets elongated from the movement range of
the ring-shaped member with respect to the female steering shaft, which
corresponds to the adjustment range of the telescopic position of the
steering wheel in a state of assembling the steering apparatus to the
vehicle body.

6. The steering apparatus according to claim 5, wherein if the diameter
enlarged portion is provided at one portion of the female spline in the
axial direction, a portion of the female spline, i.e., a portion on the
side opposite to the male spline insertion side from the diameter
enlarged portion has an end portion formed with an inclined portion on
the male spline insertion side, and the inclined portion is inclined in
such a direction that the portion on the side opposite to the male spline
insertion side approaches the center axis of the female steering shaft.

7. The steering apparatus according to claim 2, wherein the ring-shaped
member has a ring-shaped diameter large portion abutting on the female
spline and a resiliently deformable portion which gets resiliently
deformed when the large diameter portion abuts on the female spline.

8. The steering apparatus according to claim 7, wherein the ring-shaped
member is disposed in the outer peripheral side annular groove so that
the large diameter portion is directed toward the side opposite to the
male spline insertion side.

9. The steering apparatus according to claim 8, wherein the resiliently
deformable portion is formed in a cone helical shape.

10. The steering apparatus according to claim 8, wherein the resiliently
deformable portion includes a plurality of protrusions formed at the
large diameter portion.

11. The steering apparatus according to claim 3, wherein when the female
steering shaft and the male steering shaft make the relative movements in
the escaping direction as well as in the axial direction, an abutment
portion of the female spline on which the ring-shaped member abuts at the
diameter enlarged portion is formed on the face vertical to the center
axis of the female steering shaft.

12. The steering apparatus according to claim 11, wherein the diameter
enlarged portion is formed in a position deviating on such a side that a
telescopic adjustment position gets elongated from the movement range of
the ring-shaped member with respect to the female steering shaft, which
corresponds to the adjustment range of the telescopic position of the
steering wheel in a state of assembling the steering apparatus to the
vehicle body.

13. The steering apparatus according to claim 12, wherein if the diameter
enlarged portion is provided at one portion of the female spline in the
axial direction, a portion of the female spline, i.e., a portion on the
side opposite to the male spline insertion side from the diameter
enlarged portion has an end portion formed with an inclined portion on
the male spline insertion side, and the inclined portion is inclined in
such a direction that the portion on the side opposite to the male spline
insertion side approaches the center axis of the female steering shaft.

14. The steering apparatus according to claim 3, wherein the ring-shaped
member has a ring-shaped diameter large portion abutting on the female
spline and a resiliently deformable portion which gets resiliently
deformed when the large diameter portion abuts on the female spline.

15. The steering apparatus according to claim 14, wherein the ring-shaped
member is disposed in the outer peripheral side annular groove so that
the large diameter portion is directed toward the side opposite to the
male spline insertion side.

16. The steering apparatus according to claim 15, wherein the resiliently
deformable portion is formed in a cone helical shape.

17. The steering apparatus according to claim 15, wherein the resiliently
deformable portion includes a plurality of protrusions formed at the
large diameter portion.

Description:

TECHNICAL FIELD

[0001] The present invention relates generally to a steering apparatus,
and more particularly to a steering apparatus configured to adjust a
telescopic position of a steering wheel by fitting an outer column and an
inner column together slidably in an axial direction.

BACKGROUND ART

[0002] There is a telescopic type steering apparatus configured to adjust
the telescopic position of the steering wheel by fitting the outer column
and the inner column together slidably in the axial direction. Further,
as disclosed in Japanese Patent Application Laid-Open No. 2010-208588,
there is a tilt/telescopic type steering apparatus configured to adjust
both of the telescopic position and a tilt position of the steering
wheel.

[0003] In this type of steering apparatus, after completing the adjustment
of the telescopic position, an inner periphery of the outer column clamps
an outer periphery of the inner column by reducing a diameter of an outer
column having a slit, thus clamping the inner column so that the outer
column is disabled from relatively moving in the axial direction.
Further, a lower steering shaft is fitted such as being spline-fitted to
an upper steering shaft mounted with a steering wheel on the rear side of
the vehicle body to enable a telescopic movement, thereby transferring
rotations of the steering wheel to a steering gear and thus changing a
turning angle of traveling wheels.

[0004] Before mounting this type of steering apparatus on the vehicle
body, to be specific, in a state before a vehicle body fitting bracket is
fitted to the vehicle body, e.g., when delivering the steering apparatus
or when assembling a column cover, it might happen that the inner column
is released from the telescopic clamping by the outer column in the case
of operating an operation lever by mistake. In this state, when pulling
the steering wheel toward the rear side of the vehicle body, the outer
column escapes from the inner column together with the vehicle body
fitting bracket, with the result that the steering shaft is released from
the spline-fitting as the case may be.

[0005] In an electric power steering apparatus, an input shaft on the side
of the steering wheel is connected via a torsion bar to an output shaft
on the side of the traveling wheels, a torque sensor detects a distortion
of the torsion bar, torque acting on the torsion bar is detected from a
result of this distortion, and a required steering assist force is given
to the output shaft by driving the electric motor.

[0006] Therefore, it is necessary that a neutral state of the upper
steering shaft on the side of the steering wheel is made coincident
highly accurately with a neutral state of the lower steering shaft on the
side of the traveling wheels, and assembling is attained by making a
phase of the spline of the upper steering shaft to which the rotations of
the steering wheel are transferred coincident highly accurately with a
phase of the spline of the lower steering shaft to which the rotations of
the traveling wheels are transferred. Accordingly, if the steering shaft
is once released from the spline-fitting, such a problem arises that
there is a time-consuming operation of reassembling the upper steering
shaft and the lower steering shaft together in a way that makes the
spline phases thereof coincident with each other at the high accuracy.

[0008] It is an object of the present invention to provide such a steering
apparatus that, even when an inner column is released from being clamped
by an outer column in the state before fitting a vehicle body fitting
bracket to the vehicle body, any escape of the inner column from the
outer column is prevented and spline fitting of the inner column in the
outer column is maintained.

Means to Solve the Problems

[0009] The problems given above are solved by the following means. Namely,
the present invention is a steering apparatus including: an inner column;
an outer column being fitted onto the inner column so as to be relatively
movable in an axial direction; a clamp mechanism fixing a relative
position of the outer column to the inner column; a female steering shaft
being rotatably supported on any one of the inner column and the outer
column and having its inner peripheral surface formed with a female
spline; and a male steering shaft being rotatably supported on the other
of the inner column and the outer column, having its outer peripheral
surface provided with a male spline inserted and fitted in the female
spline, and being capable of moving in the axial direction with respect
to the female steering shaft and transferring torque thereto, the
steering apparatus being capable of adjusting a telescopic position of a
steering wheel fitted to the female steering shaft or the male steering
shaft, wherein the female steering shaft and the male steering shaft are
provided with a come-out preventive mechanism for preventing an axial
escape of the male steering shaft from the female steering shaft in a
state where a fitting portion between the female spline and the male
spline remains.

[0010] Further, in a preferable mode of the present invention, the
come-out preventive mechanism is configured by including: an outer
peripheral side annular groove formed in the male spline in a peripheral
direction; a resiliently deformable ring-shaped member fitted in the
outer peripheral side annular groove; and a diameter enlarged portion
provided at one portion of the female spline in the axial direction or
provided adjacently to an end portion on the side opposite to the male
spline insertion side; the diameter enlarged portion is formed to have a
diameter larger than a tooth tip circle of the female spline and have a
widthwise dimension larger than a widthwise dimension of the ring-shaped
member and is provided in a position where the fitting portion between
the female spline and the male spline remains in such a state that a
relative position of the female steering shaft to the male steering shaft
becomes a position in which the diameter enlarged portion and the outer
peripheral side annular groove are superposed in a radial direction; and
the ring-shaped member gets resiliently deformed upon the male spline
abutting on the female spline when inserted into the female spline,
enables the male spline to move with respect to the female spline in the
axial direction, resiliently returns to enlarge in diameter from a
diameter reduced state when the female steering shaft and the male
steering shaft make the relative movements in such a direction as to
escape as well as in the axial direction in a state after fitting the
female spline and the male spline together but before mounting the
steering apparatus on the vehicle body, and abuts on the female spline,
thereby preventing the axial escape of the male steering shaft from the
female steering shaft.

[0011] Moreover, in another preferable mode of the present invention, an
end portion of the female spline on the male spline insertion side is
provided with a chamfer portion; and a large diameter portion having a
diameter larger than a tooth bottom circle of the female spline is formed
at a portion of the inner peripheral surface of the female steering
shaft, i.e., at a portion on the side opposite to the male spline
insertion side; the outer peripheral side annular groove of the male
spline has its bottom surface formed closer to an inner diametrical side
than the tooth bottom circle of the male spline; the ring-shaped member
is provided with a chamfer portion on an outer diametrical side, has its
outer diameter of which a dimension is formed smaller than a diameter of
a tooth tip face of the male spline but larger than a diameter of the
tooth bottom circle of the male spline and is positioned within a range
of a radial thickness of the chamfer portion provided at the female
spline of the female steering shaft of which the outer peripheral surface
is disposed coaxially with the male steering shaft as viewed from the
axial direction of the male steering shaft; the ring-shaped member, when
the male spline is inserted into the female spline, because of the
chamfer portion on the outer diametrical side sliding on the chamfer
portion of the female spline, gets resiliently deformed to reduce in
diameter and gets movable in the axial direction within the outer
peripheral side annular groove; and a gap exists between the outer
peripheral surface of the ring-shaped member and the inner peripheral
surface of the large diameter portion when the ring-shaped member is
positioned at the large diameter portion of the female steering shaft.

[0012] Furthermore, in still another preferable mode of the present
invention, when the female steering shaft and the male steering shaft
make the relative movements in the escaping direction as well as in the
axial direction, an abutment portion of the female spline on which the
ring-shaped member abuts at the diameter enlarged portion is formed on
the face vertical to the center axis of the female steering shaft.

[0013] Moreover, in a further preferable mode of the present invention,
the diameter enlarged portion is formed in a position deviating on such a
side that a telescopic adjustment position gets elongated from the
movement range of the ring-shaped member with respect to the female
steering shaft, which corresponds to the adjustment range of the
telescopic position of the steering wheel in a state of assembling the
steering apparatus to the vehicle body.

[0014] Additionally, in a still further preferable mode of the present
invention, if the diameter enlarged portion is provided at one portion of
the female spline in the axial direction, a portion of the female spline,
i.e., a portion on the side opposite to the male spline insertion side
from the diameter enlarged portion has an end portion formed with an
inclined portion on the male spline insertion side, and the inclined
portion is inclined in such a direction that the portion on the side
opposite to the male spline insertion side approaches the center axis of
the female steering shaft.

[0015] Moreover, in a yet further preferable mode of the present
invention, the ring-shaped member has a ring-shaped diameter large
portion abutting on the female spline and a resiliently deformable
portion which gets resiliently deformed when the large diameter portion
abuts on the female spline.

[0016] Additionally, in a yet yet further preferable mode of the present
invention, the ring-shaped member is disposed in the outer peripheral
side annular groove so that the large diameter portion is directed toward
the side opposite to the male spline insertion side.

[0017] Furthermore, in an additional preferable mode of the present
invention, the resiliently deformable portion is formed in a cone helical
shape.

[0018] Moreover, in an additional preferable mode of the present
invention, the resiliently deformable portion includes a plurality of
protrusions formed at the large diameter portion.

Effects of the Invention

[0019] In the steering apparatus of the present invention, the female
steering shaft and the male steering shaft are provided with the come-out
preventive mechanism for preventing the axial escape of the male steering
shaft from the female steering shaft in the state where the fitting
portion between the female spline and the male spline remains.

[0020] Hence, according to the present invention, it is feasible to
provide the steering apparatus configured to prevent the upper steering
shaft and the lower steering shaft from being released from the
spline-fitting without any escape of the inner column from the outer
column even when the outer column telescopically unclamps the inner
column in the state before fitting the vehicle body fitting bracket of
the steering apparatus to the vehicle body

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 is a whole perspective view illustrating a state where a
steering apparatus 101 in an embodiment of the present invention is
mounted on a vehicle.

[0022]FIG. 2 is a perspective view of a principal portion of the steering
apparatus 101 in the embodiment of the present invention as viewed from a
rear side of a vehicle body.

[0023]FIG. 3 is a longitudinal sectional view illustrating a fitting
state between a female steering shaft and a male steering shaft in the
embodiment of the present invention.

[0025] FIGS. 5A and 5B illustrate a come-out preventive member in FIG. 4;
FIG. 5A is a front view of the come-out preventive member; and FIG. 5B is
a sectional view taken along the line 5B-5B in FIG. 5A.

[0026] FIGS. 6A and 6B illustrate a modified example of the come-out
preventive member; FIG. 6A is a front view of the come-out preventive
member; and FIG. 6B is a sectional view taken along the line 6B-6B in
FIG. 6A.

[0027]FIG. 7A is a front view illustrating a principal portion of a male
steering shaft in FIG. 3; and FIG. 7B is a longitudinal sectional view
illustrating a principal portion of a female steering shaft in FIG. 3.

[0028]FIG. 8 is a longitudinal sectional view illustrating a fitting
state between the female steering shaft and the male steering shaft in a
second embodiment of the present invention.

[0029]FIG. 9 is a longitudinal sectional view illustrating a principal
portion of the female steering shaft in FIG. 8.

[0030] FIG. 10A is a front view illustrating a principal portion of the
male steering shaft in the state where the come-out preventive member
according to the first embodiment is assembled; FIG. 10B is an enlarged
view of the portion in the vicinity of the come-out preventive member,
illustrating an assembly-underway state of assembling the male steering
shaft and the female steering shaft together; FIG. 10C is an enlarged
view of a portion in the vicinity of the come-out preventive member in
FIG. 10A, illustrating a state of how the come-out preventive member gets
deformed; and FIG. 10D is a plan view depicting a state of how the male
steering shaft and the female steering shaft are assembled together.

[0031]FIG. 11A is a front view illustrating the principal portion of the
male steering shaft in the state of assembling the come-out preventive
member according to a modified example of the first embodiment; FIG. 11B
is an enlarged view of a portion in the vicinity of the come-out
preventive member in FIG. 11A, illustrating an assembly-underway state of
how the male steering shaft and the female steering shaft are assembled
together; FIG. 11C is an enlarged view of the portion in the vicinity of
the come-out preventive member in FIG. 11A, depicting a state of how the
come-out preventive member gets deformed; and FIG. 11D is a front view
illustrating an assembled state of the male steering shaft and the female
steering shaft.

MODE FOR CARRYING OUT THE INVENTION

[0032] A first embodiment and a second embodiment of the present invention
will hereinafter be described based on the drawings.

[0033] To start with, directions pertaining to a steering apparatus in the
present specification will be defined. In the specification, the
directions pertaining to the steering apparatus are the same as a
back-and-forth direction, a right-and-left direction and an up-and-down
direction of a vehicle body in a state of mounting the steering apparatus
on the vehicle body unless particularly specified. The right-and-left
direction is also referred to as a vehicle widthwise direction. In FIG.
1, when viewing the sheet surface in a state where the reference numerals
and symbols in the drawings can be read in normal directions, a left
oblique downward direction on the sheet surface corresponds to a front
side with respect to the vehicle body; a right oblique upward direction
on the sheet surface corresponds to a rear side with respect to the
vehicle body; a left oblique upward direction on the sheet surface
corresponds to a right side in a vehicle widthwise direction; and a right
oblique downward direction on the sheet surface corresponds to a left
side in the vehicle widthwise direction. In FIG. 2, when viewing the
sheet surface in the state where the reference numerals and symbols in
the drawings can be read in the normal directions, a left oblique upward
direction on the sheet surface corresponds to the front side with respect
to the vehicle body; a right oblique downward direction on the sheet
surface corresponds to the rear side with respect to the vehicle body; a
right oblique upward direction on the sheet surface corresponds to the
right side in the vehicle widthwise direction; and a left oblique
downward direction on the sheet surface corresponds to the left side in
the vehicle widthwise direction. In FIGS. 3, 5B, 63, 7A, 7B, 8, 9,
10A-10D and 11A-11D, when viewing the sheet surface in the state where
the reference numerals and symbols in the drawings can be read in the
normal directions, a left direction on the sheet surface corresponds to
the front side with respect to the vehicle body; a right direction on the
sheet surface corresponds to the rear side with respect to the vehicle
body; a depthwise direction on the sheet surface corresponds to the right
side in the vehicle widthwise direction; and a near-side direction on the
sheet surface corresponds to the left side in the vehicle widthwise
direction. In FIG. 4, when viewing the sheet surface in the state where
the reference numerals and symbols in the drawings can be read in the
normal directions, the depthwise direction on the sheet surface
corresponds to the front side with respect to the vehicle body; the
near-side direction on the sheet surface corresponds to the rear side
with respect to the vehicle body; the right direction on the sheet
surface corresponds to the right side in the vehicle widthwise direction;
and the left direction on the sheet surface corresponds to the left side
in the vehicle widthwise direction. In FIGS. 5A and 6A, when viewing the
sheet surface in the state where the reference numerals and symbols in
the drawings can be read in the normal directions, the near-side
direction on the sheet surface corresponds to the front side with respect
to the vehicle body; the depthwise direction on the sheet surface
corresponds to the rear side with respect to the vehicle body; the left
direction on the sheet surface corresponds to the right side in the
vehicle widthwise direction; and the right direction on the sheet surface
corresponds to the left side in the vehicle widthwise direction.

[0034] The following respective embodiments will discuss examples of
applying the present invention to a tilt and telescopic type steering
apparatus configured to adjust both of a position of a steering wheel in
a vertical direction, i.e., a tilt adjustment position and a position in
a back-and-forth direction, i.e., a telescopic adjustment position.

First Embodiment

[0035]FIG. 1 is a whole perspective view illustrating a state of mounting
a steering apparatus 101 in a first embodiment of the present invention
on the vehicle. A steering shaft 102 is rotatably supported on the
steering apparatus 101. A steering wheel 103 is fitted to an upper end of
the steering shaft 102 on the rear side of the vehicle body, and an
intermediate shaft 105 is connected via a universal joint 104 to a lower
end of the steering shaft 102 on the front side with respect to the
vehicle body.

[0036] A universal joint 106 is connected to a lower end of the
intermediate shaft 105, and a steering gear assembly 107 configured by
including a rack-and-pinion mechanism etc is connected to the universal
joint 106.

[0037] When a driver rotationally operates the steering wheel 103, a
rotation thereof is transferred to the steering gear assembly 107 via the
steering shaft 102, the universal joint 104, the intermediate shaft 105
and universal joint 106, and a tie rod 108 is moved via the
rack-and-pinion mechanism, thereby changing a turning angle of traveling
wheels.

[0038]FIG. 2 is a perspective view of a principal portion of the steering
apparatus 101 in the first embodiment as viewed from the rear side with
respect to the vehicle body. FIG. 3 is a longitudinal sectional view
illustrating a state of how a male steering shaft is fitted in a female
steering shaft in the first embodiment of the present invention. FIG. 4
is a sectional view taken along the line 4-4 in FIG. 3. FIGS. 5A, 5B
illustrate a come-out preventive member; FIG. 5A is a front view of the
come-out preventive member; and FIG. 5B is a sectional view taken along
the line B-B in FIG. 5A. FIG. 7A is a front view illustrating the
principal portion of the male steering shaft in FIG. 3, and FIG. 7B is a
longitudinal sectional view illustrating the principal portion of the
female steering shaft in FIG. 3.

[0039] As illustrated in FIG. 2, the steering apparatus 101 in the first
embodiment of the present invention is configured by including a vehicle
body fitting bracket 2 to be fitted to the vehicle body, an inner column
3 defined as a lower column, a steering assist unit 31 defined as a power
assist mechanism, an outer column 4 defined as an upper column, etc.

[0040] A right end of the steering assist unit 31 serving as the power
assist mechanism is fixed by press-fitting to a portion of the inner
column 3 on the front side with respect to the vehicle body. The steering
assist unit 31 is configured by including a power motor 311, a reduction
gearbox unit 312, and output shaft 313, and so on. The steering assist
unit 31 is so supported as to be enabled to adjust a tilt position by
mounting a bracket 314 formed integrally with an end portion of the
steering assist unit 31 on the front side with respect to the vehicle
body in the unillustrated vehicle body via an unillustrated tilt central
shaft. Such being the configuration, the inner column 3 is so supported
as to be enabled to adjust the tilt position on the vehicle body through
the bracket 314.

[0041] As depicted in FIGS. 2 and 3, an inner peripheral surface 41 of the
outer column 4 is fitted onto an outer peripheral surface 32 of the inner
column 3 in the way of being enabled to adjust a telescopic position,
i.e., in the way of being slidable in parallel with the line of the
central axis of the inner column 3. The female steering shaft 5 is
rotatably supported on the outer column 4, and the steering wheel 103
(see FIG. 1) is fixed to the end portion of the female steering shaft 5
on the rear side with respect to the vehicle body (the right side in FIG.
3). An unillustrated slit is formed through the outer column 4 from the
outer peripheral surface 42 of the outer column 4 up to the inner
peripheral surface 41, in a portion of the outer column 4 on the lower
side with respect to the vehicle body.

[0042] The male steering shaft 6 is rotatably supported on the inner
column 3 and is spline-fitted to the female steering shaft 5.
Accordingly, the rotations of the female steering shaft 5 are transferred
to the male steering shaft 6 irrespective of the telescopic position of
the outer column 4.

[0043] The steering assist unit 31 detects torque acting on the male
steering shaft 6 and rotates the output shaft 313 by dint of a required
steering assist force by driving the power motor 311. Rotations of this
output shaft 313 are transferred to the steering gear assembly 107 via
the universal joint 104, the intermediate shaft 105 and the universal
joint 106, thereby changing the turning angle of the traveling wheels.

[0044] The vehicle body fitting bracket 2 is fitted to the front side with
respect to the vehicle body in such a manner to be able to make
collapsing movement or move forward with respect to the vehicle body when
encountering a secondary collision, and a portion of the outer column 4
on the front side with respect to the vehicle body is clamped in between
a pair of side plates 22, 22 from both of right and left sides in the
vehicle widthwise direction. Note that the collapsing movement connotes a
movement toward the front side with respect to the vehicle body while
absorbing energy of the secondary collision via an energy absorption
mechanism provided at the steering columns, the brackets, etc when
encountering the secondary collision.

[0045] The tilt position and the telescopic position of the steering wheel
103 are adjusted by rotationally operating an operation lever 21. When
rotationally operating the operation lever 21 in such a direction that
the pair of side plates 22, 22 of the vehicle body fitting bracket 2
approaches each other, the side plates 22, 22 clamp the outer peripheral
surface 42 of the outer column 4. Thereupon, the outer column 4 is
clamped by the side plates 22, 22 from the right and left sides, and the
steering wheel 103 is positioned in the tilt adjusted position.
Simultaneously, with the clamping by the side plates 22, 22, the inner
peripheral surface 41 of the outer column 4 gets reduced in diameter, and
the outer peripheral surface 32 of the inner column 3 is clamped by the
inner peripheral surface 41 of the outer column 4. The inner column 3 is
thereby clamped by the inner peripheral surface 41 of the outer column 4,
whereby the steering wheel 103 is positioned in the telescopic adjusted
position.

[0046] The telescopic clamp and the tilt clamp are unclamped by
rotationally operating the operation lever 21 in a reversed direction.
After performing telescopic and tilt unclamping operations by
rotationally operating the operation lever 21 in the reversed direction,
there are adjusted both of the position in the vertical direction, i.e.,
the tilt position and the position in the back and forth direction, i.e.,
the telescopic position of the steering wheel 103. After the adjustment,
as described above, the steering wheel 103 is positioned in the tilt
adjusted position and the telescopic adjusted position by rotationally
operating the operation lever 21 so that the side plates 22, 22 approach
each other.

[0047] As depicted in FIG. 3, the male steering shaft 6 spline-engages
with the female steering shaft 5 so that a male spline 61 formed on an
outer periphery of a portion of the male steering shaft 6 on the rear
side of the vehicle body is fitted in a female spline 51 formed in an
inner periphery of a portion of the female steering shaft 5 on the front
side with respect to the vehicle body. The female spline 51 is, as will
be described later on, configured by including a female spline portion
511 provided on the front side with respect to the vehicle body and
another female spline portion 512 provided on the rear side with respect
to the vehicle body. Further, as illustrated in FIG. 7B, a chamfer 56 is
formed at a front edge of the female spline portion 511 on the front side
with respect to the vehicle body. The chamfer 56 may be either of a
C-chamfer or an R-chamfer. As illustrated in FIGS. 3 and 7A, an outer
peripheral annular groove 62 taking a rectangular shape in section is
formed in the vicinity of the end portion of the male spline 61 of the
male steering shaft 6 on the rear side with respect to the vehicle body,
in other words, in the outer peripheral surface in the vicinity of the
end portion on an insertion side into the female steering shaft 5. A
groove bottom 621 of the outer peripheral annular groove 62 has a
diameter smaller than that of a tooth bottom circle of the male spline
61.

[0048] A come-out preventive member 7 depicted in FIGS. 5A and 5B is
fitted in and thus assembled to this outer peripheral annular groove 62.
The come-out preventive member 7 is composed of a resiliently deformable
spring steel formed as a coil taking a rectangular shape in section, in
which the configuration is a ring on the whole. More specifically, the
come-out preventive member 7 is configured as a 2-winding coil spring of
which a winding count is "2", in other words, a 2-winding cone helical
shape including a first winding 71 and a second winding 72 having a
diameter larger than that of the first winding 71. Each of ridge portions
of a wire rod is, as illustrated in FIG. 5B, formed with a chamfer 722.
The chamfer 722 may be either the C-chamfer or the R-chamfer.

[0049] Herein, respective dimensions of the come-out preventive member 7
are defined as depicted in FIG. 5B. Namely, in a free state of the
come-out preventive member 7, a ring inner diameter al is set as a
dimension of an inner diameter of an inner peripheral surface 711 of the
first winding 71, and a ring outer diameter A1 is set as a dimension of
an outer diameter of an outer peripheral surface 721 of the second
winding 72. Further, a ring width WA is set as a dimension of the
come-out preventive member 7 in an assembled state in the back-and-forth
direction of the vehicle body, and a ring thickness TA is set as a
dimension of the wire rod composing the come-out preventive member 7 in
the vertical direction of the vehicle body.

[0050] Moreover, dimensions of predetermined portions of the male steering
shaft 6 and the female steering shaft 5 are defined as illustrated in
FIGS. 7A and 7B. At first, with respect to the male steering shaft 6, an
outer peripheral annular groove bottom diameter d1 is set as a dimension
of the diameter of the groove bottom 621 of the outer peripheral annular
groove 62, a male spline small diameter d2 is set as a bottom circle
diameter of the male spline 61, a male spline large diameter d3 is set as
a tip circle diameter of the male spline 61, and an outer peripheral
annular groove width W is set as a dimension of the outer peripheral
annular groove 62 in the back-and-forth direction of the vehicle body.
The outer peripheral annular groove width W has the dimension larger than
the ring width WA of the come-out preventive member 7.

[0051] Next, with respect to the female steering shaft 5, a female spline
large diameter D2 is set as a bottom circle diameter of the female spline
51, and a female spline small diameter D3 is set as a tip circle diameter
of the female spline 51. Further, a female steering shaft inner diameter
D1 is set as a diameter of an escape hole 54, which will be described
later on, formed in a portion on the rear side with respect to the
vehicle body. Note that a chamfer 56 of the female spline 51 is formed to
have a thickness corresponding to a difference between the female spline
large diameter D2 and the female spline small diameter D3 when the female
steering shaft 5 is viewed from the axial direction from the front side
with respect to the vehicle body. That is, the chamfer 56 is formed so
that the dimension in the direction orthogonal to the axial direction of
the female steering shaft 5, i.e., the thickness dimension in the radial
direction is equal to the difference between the female spline large
diameter D2 and the female spline small diameter D3.

[0052] In the free state of the come-out preventive member 7, the ring
inner diameter al is formed slightly smaller than the outer peripheral
annular groove bottom diameter d1. Moreover, the come-out preventive
member 7 is assembled to the outer peripheral annular groove 62, in which
state the ring outer diameter A1 is formed smaller than the male spline
large diameter d3 but larger than the male spline small diameter d2. In
other words, an outer peripheral surface 71 of the come-out preventive
member 7 is positioned within a range of a tooth height of the male
spline 61 as viewed from the axial direction. Further, the ring outer
diameter A1 is, in the state where the come-out preventive member 7 is
assembled to the outer peripheral annular groove 62, formed larger than
the female spline small diameter D3 but smaller than the female spline
large diameter D2. In other words, the outer peripheral surface 721 of
the second winding 72 of the come-out preventive member 7 assembled to
the outer peripheral annular groove 62 is positioned within a range of
the thickness of the chamfer 56 of the female steering shaft 5 that is
disposed coaxially as viewed from the axial direction.

[0053] As depicted in FIGS. 3 and 7B, an inner peripheral annular groove
52 is formed in a portion, vicinal to the front end with respect to the
vehicle body, of the female steering shaft 5, i.e., formed in the inner
peripheral surface of a portion vicinal to the end portion on the
insertion side of the male steering shaft 6. The inner peripheral annular
groove 52 corresponds to a portion provided with none of the female
spline 51. In other words, the female spline 51 is configured by
including the female spline portion 511 on the front side with respect to
the vehicle body and the female spline portion 512 on the rear side with
respect to the vehicle body, and the inner peripheral annular groove 52
is formed between the female spline portion 511 on the front side with
respect to the vehicle body and the female spline portion 512 on the rear
side with respect to the vehicle body. Note that the female spline
portion 511 on the front side with respect to the vehicle body and the
female spline portion 512 on the rear side with respect to the vehicle
body are in equiphase. An edge portion, on the rear side with respect to
the vehicle body, of the female spline portion 511 on the front side with
respect to the vehicle body has a vertical face formed vertically to the
center axis of the female steering shaft 5. An edge portion, on the front
side with respect to the vehicle body, of the female spline portion 512
on the rear side with respect to the vehicle body has an inclined face
522 inclined in such a direction that the rear side with respect to the
vehicle body approaches the center axis. Furthermore, an edge portion, on
the rear side with respect to the vehicle body, of the female spline
portion 512 on the rear side with respect to the vehicle body has an
inclined face 53 inclined in such a direction that the front side with
respect to the vehicle body approaches the center axis.

[0054] A diameter of the groove bottom of the inner peripheral annular
groove 52 is formed to have the same dimension as the female spline large
diameter D2. A portion of the inner peripheral annular groove 52 on the
front side with respect to the vehicle body, in other words, on the
insertion side of the male steering shaft 6 has a shoulder portion 521
configured by including a vertical face of an end portion, on the rear
side with respect to the vehicle body, of the female spline portion 511
on the front side with respect to the vehicle body. Further, a portion of
the inner peripheral annular groove 52 on the rear side with respect to
the vehicle body, in other words, on an opposite insertion side of the
male steering shaft 6 has the inclined face 522 of an end portion, on the
front side with respect to the vehicle body, of the female spline portion
512 on the rear side with respect to the vehicle body.

[0055] Moreover, as illustrated in FIGS. 3 and 7B, the female steering
shaft 5 includes the escape hole 54 having a diameter larger than the
female spline large diameter D2, which is formed in the inner peripheral
surface of the portion closer the rear side with respect to the vehicle
body than the female spline portion 512 on the rear side with respect to
the vehicle body. A length of the escape hole 54 in the axial direction
is formed slightly longer than a telescopic movement distance between the
outer column 4 and the inner column 3, and hence the come-out preventive
member 7 is enabled to make the telescopic movement smoothly together
with the male steering shaft 6 within the escape hole 54. Moreover, a
diameter of the escape hole 54, i.e., the female steering shaft inner
diameter D1 is formed to have a dimension larger than the ring outer
diameter A1 of the escape hole 54, and therefore a gap between the escape
hole 54 and the come-out preventive member 7 is formed. Consequently,
when making the telescopic movement, the escape hole 54 does not come
into contact with the come-out preventive member 7. As a result, the
come-out preventive member 7 neither becomes a slide resistance when
making the telescopic movement nor causes an abnormal sound (noise) due
to the slide.

[0056] The outer peripheral surface 32 of the inner column 3 is fitted
into the inner peripheral surface 41 of the outer column 4, and the male
steering shaft 6 is inserted into the female steering shaft 5, at which
time the outer peripheral surface 721 of the come-out preventive member 7
contacts the tip of the female spline 51 and gets resiliently deformed to
reduce in diameter, thereby enabling the male steering shaft 6 to be
inserted into the female steering shaft 5. An in-depth description of how
the come-out preventive member 7 gets resiliently deformed on the
occasion of inserting the male steering shaft 6 into the female steering
shaft 5 will hereinafter be made.

[0057] FIG. 10A is a front view illustrating a principal portion of the
male steering shaft 6 in the state where the come-out preventive member 7
according to the first embodiment is assembled; FIG. 10B is an enlarged
view of the portion in the vicinity of the come-out preventive member 7,
illustrating an assembly-underway state of assembling the male steering
shaft 6 and the female steering shaft 5 together; FIG. 10C is an enlarged
view of a portion in the vicinity of the come-out preventive member 7 in
FIG. 10A, illustrating a state of how the come-out preventive member 7
gets deformed; and FIG. 10D is a plan view depicting a state of how the
male steering shaft 6 and the female steering shaft 5 are assembled
together.

[0058] As illustrated in FIG. 10A, in the state of assembling the come-out
preventive member 7 into the outer peripheral annular groove 62, the
outer peripheral surface of the first winding 71 is positioned closer to
the inner diametrical side than the tooth bottom of the male spline 61,
and the outer peripheral surface 721 of the second winding 72 is
positioned closer to the inner diametrical side than the tooth tip and on
the outer diametrical side from the tooth bottom of the male spline 61.
Further, in the come-out preventive member 7, the first winding 71 is
disposed on the rear side with respect to the vehicle body, and the
second winding 72 is disposed on the front side with respect to the
vehicle body. The come-out preventive member 7 is disposed in this
direction, thereby improving an assembling property between the male
steering shaft 6 and the female steering shaft 5. The ring inner diameter
al (see FIG. 5B) of the come-out preventive member 7 is formed slightly
smaller than the outer peripheral annular groove bottom diameter d1 (see
FIG. 7A), and hence the come-out preventive member 7 is fitted with no
backlash by clamping the outer peripheral annular groove 62.

[0059] From this state, the end portion of the male steering shaft 6 on
the rear side with respect to the vehicle body and the end portion of the
female steering shaft 5 on the front side with respect to the vehicle
body are set in a face-to-face relation with respect to the axial
direction, and the male spline 61 and the female spline 51 are fitted
together by moving the male steering shaft 6 and the female steering
shaft 5 in such a direction as to approach each other. Thereupon, the end
portion of the female spline 51 on the front side with respect to the
vehicle body abuts on the portion of the outer diametrical side of the
second winding 72 of the come-out preventive member 7. Furthermore, when
fitting the male spline 61 and the female spline 51 together, the
come-out preventive member 7 is, as illustrated in FIG. 10B, pushed by
the female spline 51, and the whole come-out preventive member 7 is moved
up to the end portion of the outer peripheral annular groove 62 on the
front side with respect to the vehicle body.

[0060] The chamfer 56 is formed at the end portion of the female spline 51
on the front side with respect to the vehicle body, and the chamfer 722
is also formed at the portion of the outer diametrical side of the second
winding 72 of the come-out preventive member 7. Therefore, when further
fitting the male spline 61 and the female spline 51 together, the chamfer
56 and the chamfer 722 slide on each other. Then, as depicted in FIG.
10C, the second winding 72 smoothly relative moves to the tooth tip of
the female spline 51 from the chamfer 56, thereby getting resiliently
deformed to reduce in diameter. Simultaneously, the whole come-out
preventive member 7 gets resiliently deformed and stretches in the
back-and-forth direction of the vehicle body. At this time, the come-out
preventive member 7 is positioned at the end portion of the outer
peripheral annular groove 62 but is disabled from stretching toward the
front side of the vehicle body and therefore stretches, it follows,
toward the rear side with respect to the vehicle body. As a result, it
follows that the first winding 71 moves toward the rear side with respect
to the vehicle body as depicted in FIG. 100. Thus, the outer peripheral
annular groove width W (see FIG. 7A) is formed to have a dimension well
larger than the ring width WA (see FIG. 5B) of the come-out preventive
member 7 so that the come-out preventive member 7 can stretch in the
back-and-forth direction of the vehicle body. Thereafter, as illustrated
in FIG. 10D, the male steering shaft 6 is assembled to the female
steering shaft 5 by further fitting the male spline 61 and the female
spline 51 together.

[0061] Upon completion of inserting the male steering shaft 6 into the
female steering shaft 5 and when the come-out preventive member 7 reaches
the escape hole 54, the second winding 72 of the come-out preventive
member 7 resiliently returns and enlarges in diameter, and simultaneously
the whole come-out preventive member 7 resiliently returns to get
contracted in the back-and-forth direction of the vehicle body. As a
result, the ring outer diameter A1 (see FIG. 5B) of the come-out
preventive member 7 comes to the same state as the state depicted in FIG.
10A. In this state, the male steering shaft 6 is spline-fitted in the
female steering shaft 5 and is telescopically movable, while the come-out
preventive member 7 is telescopically movable together with the male
steering shaft 6 within the escape hole 54. The inner peripheral surface
711 of the come-out preventive member 7 clamps, as described above, the
groove bottom 621 of the outer peripheral annular groove 62 of the male
steering shaft 6, and hence the come-out preventive member 7 is fitted in
the outer peripheral annular groove 62 without any backlash, resulting in
no emission of the abnormal sound (noise) during the drive operation.

[0062] In the normal state after assembling the steering apparatus in the
vehicle body, when the come-out preventive member 7 adjusts the
telescopic position from the state of positioning within the range of the
escape hole 54, the outer peripheral surface 721 of the come-out
preventive member 7 abuts on the inclined face 53 of the end portion, on
the rear side with respect to the vehicle body, of the female spline
portion 512 on the rear side with respect to the vehicle body by pulling
the outer column 4 toward the rear side with respect to the vehicle body,
at which time the come-out preventive member 7 gets smoothly shrunk in
diameter because of the chamfer 722 being formed on the outer peripheral
surface 721 of the second winding 72 of the come-out preventive member 7
and because of the second winding 72 being guided by the inclined face
53. It is therefore feasible to make the telescopic movement by further
pulling the outer column 4 toward the rear side with respect to the
vehicle body while bringing the outer peripheral surface 721 of the
come-out preventive member 7 into contact with the tooth tip of the
female spline portion 512.

[0063] Note that the adjustment range of the telescopic position of the
steering wheel 103 (see FIG. 1) in the normal state after being assembled
to the vehicle body is set to a range till the come-out preventive member
7 moves to the position in the vicinity of the end portion, on the front
side with respect to the vehicle body, of the female spline portion 512
from the predetermined position of the escape hole 54. Namely, the
come-out preventive member 7 is positioned in the predetermined position
of the escape hole 54 when a length of the portion where the male spline
61 of the male steering shaft 6 engages with the female spline 51 of the
female steering shaft 5 is maximum, i.e., when the steering shaft becomes
shortest. Further, the come-out preventive member 7 is positioned in the
vicinity of the end portion, on the front side with respect to the
vehicle body, of the female spline portion 512 on the rear side with
respect to the vehicle body when the length of the portion where the male
spline 61 engages with the female spline 51 is minimum, i.e., when the
steering shaft becomes longest. Such being the configuration, the inner
peripheral annular groove 52 is formed in the position deviating on such
a side that the telescopic adjustment position gets elongated from the
movement range of the come-out preventive member 7 with respect to the
female spline shaft 5, which corresponds to the adjustment range of the
telescopic position of the steering wheel 103. That is, in the adjustment
range of the normal telescopic position, it does not happen that the
come-out preventive member 7 is positioned in the inner peripheral
annular groove 52. In other words, it follows that the come-out
preventive member 7 is positioned in the inner peripheral annular groove
52 when in the fitting state where the length of the portion where the
male steering shaft 6 is fitted in the female steering shaft 5 is shorter
than when coming to the shortest range of the normal adjustment.

[0064] Before mounting the steering apparatus 101 having the
configurations of the steering shafts such as this, it might happen that
the inner column 3 is released from the telescopic clamping and the tilt
clamping by the outer column 4 when operating the operation lever 21 by
mistake, to be specific, in the state before assembling the vehicle body
fitting bracket 2 to the vehicle body such as in delivery and assembling
an unillustrated column cover. In the first embodiment, in this case,
when making the relative movement in such a direction that the male
steering shaft 6 escapes from the female steering shaft 5, the come-out
preventive member 7 is intruded into the inner peripheral annular groove
52 in the vicinity of the end portion of the female spline 51 on the
front side with respect to the vehicle body to enlarge in diameter.
Thereupon, the second winding 72 of the come-out preventive member 7
abuts on the shoulder portion 521 of the end portion of the inner
peripheral annular groove 52 on the front side with respect to the
vehicle body. At this time, the abutment portion where the second winding
72 abuts on the shoulder portion 521 is an end face of the second winding
72 on the front side with respect to the vehicle body. The shoulder
portion 521 is a vertical face on which the end portion of the female
spline portion 511 on the rear side with respect to the vehicle body is
formed vertically to the center axis of the female steering shaft 5, and
hence the second winding 72 of the come-out preventive member 7 cannot
reduce in diameter even when abutting on the shoulder portion 521.
Consequently, the male steering shaft 6 is disabled from moving further
in such a direction as to escape from the female steering shaft 5. As a
result, it is feasible to surely prevent the escape of the male steering
shaft 6 from the female steering shaft 5. Namely, the inner column 3 can
be certainly prevented from escaping out of the outer column 4.

[0065] Furthermore, in this state, the male spline 61 of the portion
closer to the front side with respect to the vehicle body than the outer
peripheral annular groove 62 is fitted in the female spline portion 511
on the front side with respect to the vehicle body. Moreover, the male
spline 61 of the portion closer to the rear side with respect to the
vehicle body than the outer peripheral annular groove 62 is fitted in the
female spline portion 512 on the rear side with respect to the vehicle
body. The phase of the male spline 61 and the phase of the female spline
51 are thus retained.

[0066] In this way, the second winding 72 of the portion, exhibiting the
large diameter, of the come-out preventive member 7 abuts on the shoulder
portion 521, thereby preventing the male steering shaft 6 from escaping
out of the female steering shaft 5. That is, the come-out preventive
member 7 has the configuration that the second winding 72 having the
large diameter builds up the come-out preventive portion to prevent the
male steering shaft 6 from coming out the female steering shaft 5, and
the whole portion including the first winding 71 builds up the resilient
deforming portion which gets resiliently deformed when assembling the
male steering shaft 6 and the female steering shaft 5 together.

[0067] When the outer column 4 is telescopically moved as pushed toward
the front side with respect to the vehicle body from the state where the
come-out preventive member 7 is intruded into the inner peripheral
annular groove 52 of the female spline 51 to enlarge in diameter, the
outer peripheral surface 721 of the come-out preventive member 7 is
guided to the inclined face 522 of the end portion of the inner
peripheral annular groove 52 on the rear side of the vehicle body and
thus smoothly reduces in diameter. Accordingly, the telescopic movement
can be continued by further pushing the outer column 4 toward the front
side with respect to the vehicle body while bringing the outer peripheral
surface 721 of the come-out preventive member 7 into contact with the
tooth tip of the female spline portion 512 on the rear side with respect
to the vehicle body. Thus, the male steering shaft 6 is prevented from
escaping out of the female steering shaft 5, and further the female
steering shaft 5 and the male steering shaft 6 can be returned to the
original states through the normal telescopic movements.

[0068] In the first embodiment, the male steering shaft 6 can be surely
prevented from escaping out of the female steering shaft 5 simply by
assembling the male steering shaft 6 into the female steering shaft 5 in
the normal assembling procedure, and therefore it is preferable that the
assembly work is simple. Further, the come-out preventive structure
affects just slightly the external shape of the steering apparatus and
the vehicle body because of being the internal structure built up within
the outer column 4 and the inner column 3 and can be applied to many
types of steering apparatuses.

[0069] Note that the come-out preventive member 7 may be configured by use
of a wire in the first embodiment. The wire take a circular shape in
section and therefore has no necessity for undergoing the chamfering,
whereby the number of steps and a manufacturing cost can be reduced.

Modified Example

[0070] Next, a modified example of the first embodiment will be described.
The modified example is different in terms of a form of the come-out
preventive member from the first embodiment, but other constructions are
the same. Therefore, in the following discussion, the description will be
focused on the different configuration, and the repetitive explanations
are omitted as the case may be. Further, the same components are marked
with the same numbers and symbols, and the description will be made by
diverting the drawings used in the first embodiment to the modified
example.

[0071] FIGS. 6A and 6B illustrate modified examples of the come-out
preventive member; FIG. 6A is a front view of the modified example of the
come-out preventive member; and FIG. 6B is a sectional view taken along
the line 6B-6B in FIG. 6A. A come-out preventive member 8 in the modified
example is configured in a substantially ring-like C-shape with a circle
being partially notched by use of the wire rod composed of the
resiliently deformable spring steel and taking the rectangular shape in
section. An inner peripheral surface 81 of a C-shaped portion 80 formed
in the C-shape is provided with seven pieces of protrusions 82 protruding
toward the axial center and disposed at equal intervals in the peripheral
direction. One of these seven protrusions 82 is in the face-to-face
relation with the notched portion of the C-shaped portion 80, while the
remaining protrusions 82 are paired in the face-to-face relation about
the center axis of the C-shaped portion 80, thus forming three pairs of
protrusions. Each of the protrusions 82 is formed by its being bent just
at a predetermined angle α in the same direction in the way of
being raised from the inner peripheral surface 81 as viewed from the
direction orthogonal to the center axis.

[0072] Herein, the respective dimensions of the come-out preventive member
8 will be defined as illustrated in FIGS. 6A and 6B. Specifically, a ring
outer diameter B1 is set as a dimension of the outer diameter of the
outer peripheral surface 83 of the C-shaped portion 80, and a ring inner
diameter b1 is set as a distance between tips of the face-to-face
protrusions 82, 82. Further, a ring width WB is set as a dimension in the
back-and-forth direction of the vehicle body in the state where the
come-out preventive member 8 is assembled, and a ring thickness TB is set
as a dimension of the wire rod composing the C-shaped portion 80 in the
back-and-forth direction of the vehicle body. Note that the outer
peripheral annular groove width W (see FIG. 7A) has a dimension larger
than the ring width WB.

[0073] In the free state of the come-out preventive member 8, a protrusion
edge of the protrusion 82 is formed to protrude toward the inner
diametrical side from the groove bottom 621 of the outer peripheral
annular groove 62.

[0074] Moreover, in the state of fitting and assembling the come-out
preventive member 8 in the outer peripheral annular groove 62 of the male
steering shaft 6, the ring outer diameter B1 is formed to have a
dimension smaller than a male spline large diameter d3 but larger than a
male spline small diameter d2. In other words, the outer peripheral
surface 83 of the come-out preventive member 8 is positioned within a
range of the tooth height of the male spline 61 as viewed from the axial
direction. Still further, the ring outer, diameter B1 is formed larger
than the female spline small diameter D3 but smaller than the female
spline large diameter D2 in the state of assembling the come-out
preventive member 8 in the outer peripheral annular groove 62. In other
words, the outer peripheral surface 83 of the come-out preventive member
8 assembled in the outer peripheral annular groove 62 is positioned
within the range of the diametrical thickness of the chamfer 56 of the
female steering shaft 5 that is coaxially disposed as viewed from the
axial direction. The protrusion 82 is bent just at the angle α,
thereby facilitating resilient deformation of the protrusion 82 and thus
enabling the C-shaped portion 80 of the come-out preventive member 8 to
smoothly enlarge and reduce in diameter.

[0075] The resilient deformation of the come-out preventive member 8 when
inserting the male steering shaft 6 into the female steering shaft 5 will
hereinafter be described.

[0076]FIG. 11A is a front view illustrating the principal portion of the
male steering shaft 6 in the state of assembling the come-out preventive
member 8 according to the modified example of the first embodiment; FIG.
11B is an enlarged view of a portion in the vicinity of the come-out
preventive member 8 in FIG. 11A, illustrating an assembly-underway state
of how the male steering shaft 6 and the female steering shaft 5 are
assembled together; FIG. 11C is an enlarged view of the portion in the
vicinity of the come-out preventive member 8 in FIG. 11A, depicting a
state of how the come-out preventive member 8 gets deformed; and FIG. 11D
is a front view illustrating an assembled state of the male steering
shaft 6 and the female steering shaft 5.

[0077] As illustrated in FIG. 11A, in the state where the come-out
preventive member 8 is assembled in the outer peripheral annular groove
62, the outer peripheral surface 83 is positioned closer to the inner
diametrical side than the tooth tip of the male spline 61. The come-out
preventive member 8 is disposed so that the tip side of each protrusion
82 is directed to the rear side with respect to the vehicle body, while
the C-shaped portion 80 is directed to the front side with respect to the
vehicle body. The come-out preventive member 8 is disposed in this
direction, thereby improving the assembling property between the male
steering shaft 6 and the female steering shaft 5. The come-out preventive
member 8 is configured such that the protrusion edge of the protrusion 82
gets more protruded on the inner diametrical side than the groove bottom
621 of the outer peripheral annular groove 62 in the free state, and
hence the ring inner diameter b1 (see FIG. 6A) of the come-out preventive
member 8 is formed slightly smaller than the outer peripheral annular
groove bottom diameter d1 (see FIG. 7A). Therefore, the come-out
preventive member 8 is fitted without any backlash in the manner that the
respective protrusions 82 clamp the outer peripheral annular groove 62.

[0078] From this state, the end portion of the male steering shaft 6 on
the rear side with respect to the vehicle body and the end portion of the
female steering shaft 5 on the front side with respect to the vehicle
body are set in the opposed or face-to-face relation in the axial
direction, and the male steering shaft 6 and the female steering shaft 5
are fitted together by moving these shafts 5, 6 in such a direction as to
approach each other. Namely, the male spline 61 and the female spline 51
are fitted together. Thereupon, as illustrated in FIG. 11B, the end
portion of the female spline 51 abuts on the C-shaped portion 80 of the
come-out preventive member 8.

[0079] The end portion of the female spline 51 on the front side of the
vehicle body is formed with the chamfer 56, and the outer peripheral
surface 83 of the C-shaped portion 80 is also formed with a chamfer 831
whereby the chamfer 56 and the chamfer 831 slide on each other when the
male steering shaft 6 is further fitted in the female steering shaft 5.
Then, as illustrated in FIG. 11C, the C-shaped portion 80 smoothly
relatively moves toward the tooth tip from the chamfer 56 of the female
spline 51, whereby a gap of the notched portion is narrowed to reduce in
diameter. Simultaneously, each protrusion 82 gets resiliently deformed to
fall down in the direction parallel to the groove bottom 621 of the outer
peripheral annular groove 62. Thus, the outer peripheral annular groove
width W (see FIG. 7A) is formed to have a dimension well larger than the
ring width WB (see FIG. 6B) of the come-out preventive member 8 to enable
the C-shaped portion 80 of the come-out preventive member 8 to move in
the back-and-forth direction of the vehicle body. Thereafter, the male
spline 61 is further fitted in the female spline 51, and, as depicted in
FIG. 11D, the male steering shaft 6 and the female steering shaft 5 are
assembled together. Note that the come-out preventive member 8 is
entirely pushed by the female spline 51, then moved to the end portion of
the outer peripheral annular groove 62 on the front side of the vehicle
body and thereafter reduces in diameter and gets resiliently deformed as
the case may be.

[0080] Upon completion of inserting the male steering shaft 6 into the
female steering shaft 5 and when the come-out preventive member 8 reaches
the escape hole 54, the C-shaped portion 80 of the come-out preventive
member 8 resiliently returns to enlarge in diameter, and the ring outer
diameter B1 of the come-out preventive member 8 comes to the same state
as illustrated in FIG. 11A.

[0081] Thus, the male steering shaft 6 is spline-fitted in the female
steering shaft 5 to be telescopically movable, and the come-out
preventive member 8 becomes movable together with the male steering shaft
6 within the escape hole 54. The protrusion edge of each of the
protrusions 82 clamps, as described above, the groove bottom 621 of the
outer peripheral annular groove 62 of the male steering shaft 6, and
hence the come-out preventive member 8 is fitted in the outer peripheral
annular groove 62 without any backlash, which does not cause the abnormal
sound during the drive operation. Moreover, the angle α of the
protrusion 82 can be set to an angle which facilitates the assembly
between the male steering shaft 6 and the female steering shaft 5,
depending on the type of the steering apparatus. Other effects are the
same as those in the first embodiment.

[0082] In the present modified example also, before mounting the steering
apparatus 101 on the vehicle body, when the operation lever 21 is
operated by mistake and the inner column 3 is released from the
telescopic clamping and the tilt clamping, in which case the male
steering shaft 6 can be prevented from escaping out of the female
steering shaft 5.

[0083] When making the relative movement in such a direction that the male
steering shaft 6 escapes from the female steering shaft 5, the C-shaped
portion 80 of the come-out preventive member 8 is intruded into the inner
annular groove 52 of the female spline 51 and resiliently returns to
enlarge in diameter. Thereupon, the C-shaped portion 80 of the come-out
preventive member 8 abuts on the shoulder portion 521 of the end portion
of the inner annular groove 52 on the front side with respect to the
vehicle body. At this time, the abutment portion of the C-shaped portion
80, which abuts on the shoulder portion 521, is the end face of the
C-shaped portion 80 on the front side with respect to the vehicle body.
The shoulder portion 521 is a vertical face on which the end portion of
the female spline portion 511 on the rear side with respect to the
vehicle body is formed vertically to the center axis of the female
steering shaft 5, and hence the C-shaped portion 80 of the come-out
preventive member 8 cannot reduce in diameter even when abutting on the
shoulder portion 521. Consequently, the male steering shaft 6 is disabled
from moving further in such a direction as to escape from the female
steering shaft 5. As a result, it is feasible to surely prevent the
escape of the male steering shaft 6 from the female steering shaft 5.
Namely, the inner column 3 can be certainly prevented from escaping out
of the outer column 4.

[0084] Furthermore, in this state, the male spline 61 of the portion
closer to the front side with respect to the vehicle body than the outer
peripheral annular groove 62 is fitted in the female spline portion 511
on the front side with respect to the vehicle body. Moreover, the male
spline 61 of the portion closer to the rear side of the vehicle body than
the outer peripheral annular groove 62 is fitted in the female spline
portion 512 on the rear side of the vehicle body. The phase of the male
spline 61 and the phase of the female spline 51 are thus retained.

[0085] In this way, the C-shaped portion 80 of the come-out preventive
member 8 abuts on the shoulder portion 521, thereby preventing the male
steering shaft 6 from escaping out of the female steering shaft 5. That
is, the come-out preventive member 8 has the configuration that the
C-shaped portion 80 taking substantially the ring-shape and having the
large diameter builds up the come-out preventive portion to prevent the
male steering shaft 6 from coming out the female steering shaft 5, and
the respective protrusions 82 provided on the inner diametrical side of
the C-shaped portion 80 build up the resilient deforming portion which
gets resiliently deformed when assembling the male steering shaft 6 and
the female steering shaft 5 together.

[0086] When the outer column 4 is telescopically moved as pushed toward
the front side of the vehicle body from the state where the C-shaped
portion 80 of the come-out preventive member 8 is intruded into the inner
peripheral annular groove 52 of the female spline 51 to enlarge in
diameter, the outer peripheral surface 83 of the C-shaped portion 80 is
guided to the inclined face 522 of the end portion of the inner
peripheral annular groove 52 on the rear side with respect to the vehicle
body, whereby the C-shaped portion 80 smoothly reduces in diameter.
Accordingly, the telescopic movement can be continued by further pushing
the outer column 4 toward the front side of the vehicle body while
bringing the outer peripheral surface 83 of the C-shaped portion 80 into
contact with the tooth tip of the female spline portion 512 on the rear
side with respect to the vehicle body. Thus, in the present modified
example also, the male steering shaft 6 is prevented from escaping out of
the female steering shaft 5, and further the female steering shaft 5 and
the male steering shaft 6 can be returned to the original states through
the normal telescopic movements. Other effects are the same as those in
the first embodiment.

Second Embodiment

[0087] Next, a second embodiment will be described. FIG. 8 is a
longitudinal sectional view illustrating a fitted state between the
female steering shaft 5 and the male steering shaft 6 in the second
embodiment of the present invention. FIG. 8 is a longitudinal sectional
view illustrating a principal portion of the female steering shaft. In
the following discussion, the description will be focused on the
different configuration, and the repetitive explanations are omitted as
the case may be. Further, the same components are marked with the same
numbers and symbols, and the description will be made by diverting the
drawings used in the first embodiment to the second embodiment. The
second embodiment is given by way of a modified example of the first
embodiment, in which the shape of the female steering shaft 5 is changed.

[0088] In the second embodiment, the male steering shaft 6 and the
come-out preventive member 7 are the same as those in the first
embodiment, and hence the in-depth descriptions of the male steering
shaft 6 and the come-out preventive member 7 are omitted. To be specific,
the coil-like come-out preventive member 7 is assembled in the outer
peripheral annular groove 62 in the vicinity of the end portion of the
male spline 61 on the rear side with respect to the vehicle body.
Further, in the second embodiment, as illustrated in FIG. 9, unlike the
first embodiment, the inner peripheral annular groove 52 is not formed in
the vicinity of the end portion of the female spline 51 of the female
steering shaft 5, i.e., in the inner peripheral surface in the vicinity
of the end portion on the insertion side of the male steering shaft 6.

[0089] The escape hole 54 of which the diameter is larger than the
diameter of the tooth bottom circle of the female spline 51, i.e., than
the female spline large diameter D2 is formed in the inner peripheral
surface of the portion of the female steering shaft 5, which is closer to
the rear side of the vehicle body than the female spline 51. The length
of the escape hole 54 in the axial direction is formed slightly longer
than the telescopic movement distance between the outer column 4 and the
inner column 3, and hence the come-out preventive member 7 is enabled to
make the telescopic movement smoothly together with the male steering
shaft 6 within the escape hole 54.

[0090] Moreover, a shoulder portion 55, which connects the female spline
51 to the escape hole 54, is formed at the end portion of the female
spline 51 on the rear side with respect to the vehicle body, i.e., at the
end portion of the male steering shaft 6 on the opposite side to the
insertion side thereof. The shoulder portion 55 is a vertical face on
which the end portion of the female spline 51 on the rear side with
respect to the vehicle body is formed vertically to the center axis of
the female steering shaft 5.

[0091] Similarly to the first embodiment, the outer peripheral surface 32
of the inner column 3 is fitted in the inner peripheral surface 41 of the
outer column 4, and, when inserting the male steering shaft 6 into the
female steering shaft 5, the outer peripheral surface 721 of the second
winding 72 of the come-out preventive member 7 comes into contact with
the chamfer 56 of the female spline 51 and with the tooth tip and gets
resiliently deformed to reduce in diameter, thereby enabling the male
steering shaft 6 to be inserted into the female steering shaft 5.

[0092] Upon completion of inserting the male steering shaft 6 into the
female steering shaft 5 and when the come-out preventive member 7 moves
to the escape hole 54, the outer peripheral surface 721 of the second
winding 72 of the come-out preventive member 7 gets resiliently returned
to enlarge in diameter, and the dimension of the outer diameter of the
outer peripheral surface 721 of the come-out preventive member 7, i.e.,
the outer diameter A1 of the ring A (see FIG. 5B) becomes the same state
as the state depicted in FIG. 10A. In this state, the male steering shaft
6 is spline-fitted in the female steering shaft 5 and is telescopically
movable, and the come-out preventive member 7 is also telescopically
movable together with the male steering shaft 6 within the escape hole
54.

[0093] In the state before fitting the vehicle body fitting bracket 2 to
the vehicle body, it might happen that the inner column 3 is released
from the telescopic clamping and the tilt clamping by the outer column 4
when operating the operation lever 21 by mistake. In the case such as
this, when the male steering shaft 6 is to escape from the female
steering shaft 5, the come-out preventive member 7 abuts on the end
portion of the female spline 51 on the rear side with respect to the
vehicle body, i.e., the shoulder portion 55 on the opposite side to the
insertion side of the male spline 61. The shoulder portion 55 is the
vertical face on which the end portion of the female spline 51 on the
rear side with respect to the vehicle body is formed vertically to the
center axis of the female steering shaft 5, and hence the second winding
72 of the come-out preventive member 7 does not reduce in diameter after
abutting on the shoulder portion 55. Therefore, the male steering shaft 6
cannot move any further in such a direction as to escape from the female
steering shaft 5. As a result, it is feasible to surely prevent the male
steering shaft 6 from escaping out of the female steering shaft 5.
Namely, the inner column 3 can be certainly prevented from escaping out
of the outer column 4.

[0094] Moreover, in this state, the male spline 61 of the portion closer
to the front side with respect to the vehicle body than the outer
peripheral annular groove 62 is fitted in the female spline 51. Thus, the
phase of the male spline 61 and the phase of the female spline 51 are
retained.

[0095] Note that the shoulder portion 55 is formed beyond the movement
range of the come-out preventive member 7 with respect to the female
spline shaft 5, which corresponds to the adjustment range of the
telescopic position of the steering wheel 103. That is, in the adjustment
range of the normal telescopic position after being mounted on the
vehicle body, it does not happen that the come-out preventive member 7
abuts on the shoulder portion 55. Other constructions and effects are the
same as those in the first embodiment. Note that the effect is the same
if the come-out preventive member 8 is used as a substitute for the
come-out preventive member 7 in the second embodiment.

[0096] Each of the embodiments given above has discussed the example in
which the male steering shaft 6 is spline fitted in the female steering
shaft 5, however, the present invention is not limited to the spline
shaft, and a non-circular shaft such as a serration shaft capable of
transferring the rotary torque may be sufficient. Moreover, each of the
embodiments has discussed the example applied to steering apparatus in
which the female steering shaft 5 is rotatably supported on the outer
column 4, and the male steering shaft 6 is rotatably supported on the
inner column 3, however, the present invention may also be applied to a
steering apparatus in which the female steering shaft 5 is rotatably
supported on the inner column 3, and the male steering shaft 6 is
rotatably supported on the outer column 4.

[0097] Still further, each of the embodiments has discussed the example of
applying the present invention to the tilt/telescopic type steering
apparatus capable of adjusting both of the tilt position and the
telescopic position, however, the present invention may also be applied
to a telescopic type steering apparatus capable of adjusting only the
telescopic position.

[0098] Yet further, when the come-out preventive member 7 or the come-out
preventive member 8 slides on the female spline 51, i.e., when making the
telescopic movement, plating may be applied to the come-out preventive
member 7 or the come-out preventive member 8 in order to prevent the
abnormal sound due to the slide between the come-out preventive member 7
or the come-out preventive member 8 and the female spline 51. The plating
exhibits an effect in reducing a coefficient of friction and enables the
steel to be worked at a low cost. Moreover, the come-out preventive
member 7 and the come-out preventive member 8 may be coated with a low
friction material or grease. All of these contrivances have the effect in
reducing the coefficient of friction of the come-out preventive member 7
and the come-out preventive member 8, and can prevent, similarly to the
case of applying the plating, the abnormal sound due to the slide between
the come-out preventive member 7 or the come-out preventive member 8 and
the female spline 51.